In the evening, the skies pulse with lightning, but there is nothing yet to relieve the heat.

BBC: Before the storm in Cameroon

Nearly half of those deaths were caused by exposure to the cold--twice the number of heat-related deaths and more than all of the combined deaths resulting from lightning, storms, floods, earthquakes, landslides and other natural events.

FORBES: Magazine Article

As Darwin had suggested, heat and electricity were added to the mix to mimic the effects of vulcanism and lightning (later experiments also included light of the ultraviolet variety, to represent the powerful rays of the young sun).

ECONOMIST: Stanley Miller